A Stepwise Multichannel MAC Protocol for Improving Bandwidth Utilization in Wireless Ad Hoc Networks

A cooperative CDMA-based multi-channel MAC protocol for mobile ad hoc networks

The so-called Internet of Things (IoT) aims at connecting every single object to the Internet with the purpose to automate every aspect of daily life. The IoT relies heavily on wireless low-power and lossy networks (LLNs) that collect information from the physical world and send the measurements to data aggregation and processing nodes. Most LLNs operate in the non-licensed industrial, scientific, and medical radio band, which is shared by a considerable number of systems. Coexisting wireless systems cause interference to each other, limiting their achievable performance. Multichannel communications enable frequency diversity, which in turn provides robustness against interference as well as increased network capacity. There is a considerable interest in multichannel medium access control (MAC) protocols for LLNs, including an evolving standard for the MAC layer of LLNs. In this paper, we review the latest advances in the topic and introduce a new classification framework for multichannel MAC protocols for LLNs. While our framework builds on previous review and classification studies, it adds aspects of a MAC protocol that reflect its interactions with the surrounding network stack. Seeing the resource constraints of the LLN devices, the study of such interactions—which is missing in prior classification efforts—can be the key for improving future designs. Relevant protocols published since 2006 are discussed and classified using the presented framework, including the recent multichannel MAC protocols for LLNs, such as the latest version of the IEEE 802.15.4 standard for time slotted channel hopping.

We propose a cross-layer based multi-channel Medium Access Control (MAC) protocol to maximize the utilization of the leftover spectrum of primary user channels in cognitive radio networks. This protocol integrates the spectrum sensing at Physical layer and the packet scheduling at the MAC layer for mobile ad-hoc networks. With a TDMA-based control channel, we have a scheme to handle collision. Moreover, our scheme is suitable for heterogeneous network with different device capabilities. We formulate the channel allocation problem as a constrained optimization problem and propose strategies to handle channel allocation based on graph theoretic principles, specifically using Weighted Bipartite Graph Matching technique. We name our proposed modeling as Weighted Bipartite Multi-Vertex Matching (WBMM) and describes three different schemes based on this model. We conduct extensive simulation studies to analyze and compare the performance of the proposed strategies.

This paper proposes a novel multi-channel medium access control (MAC) that is based on CSMA/CA mechanism. The objective of this research is to evaluate the possibility of increasing network capacity and addressing collision problem of wireless sensor network comprising of low spec physical hardware. The proposed protocol can be implemented into wireless sensor network platform i.e. MICAz, Tmote-Sky without any additional hardware or firmware. Experiment results show that the proposed protocol can effectively improve the network performance compared with traditional single channel MAC.

Existing multi-channel Medium Access Control (MAC) protocols have been demonstrated to significantly increase wireless network performance compared to single channel MAC protocols. Traditionally, the channelization structure in IEEE 802.11 based wireless networks is pre-configured, and the entire available spectrum is divided into subchannels and equal channel widths. In contrast, this paper presents a Traffic-Aware Channelization MAC (TAC-MAC) protocol for wireless ad hoc networks, where each node is equipped with a single half duplex transceiver. TAC-MAC works in a distributed, fine-grained manner, which dynamically divides variable-width subchannels and allocates subchannel width based on the Orthogonal Frequency Division Multiplexing (OFDM) technique according to the traffic demands of nodes. Simulations show that the TAC-MAC can significantly improve network throughput and reduce packet delay compared with both fixed-width multi-channel MAC and single channel 802.11 protocols, which illustrates a new paradigm for high-efficient multi-channel MAC design in wireless ad hoc networks.

Traditional IEEE 802.11-based networks use only a single channel to ensure connectivity; however, multi-channel capability is available to provide higher network throughput by allowing simultaneous multiple transmissions that do not interfere with each other. The use of multiple channels raises several new challenges: mainly finding the receiver, scheduling the next transmission, balancing the load among channels, and dealing with multi-channel hidden terminals. This paper proposes a novel and efficient, asynchronous multi-channel medium-access control (MAC) protocol using a single transceiver. The key technique is that the proposed protocol separates searching and scheduling processes where searching users switch channels faster than regular users. Simulation results indicate that the proposed protocol achieves up to 14.10 Mbps network throughput, whereas the IEEE 802.11 MAC protocol, with a single channel, provides only 4.35 Mbps in the best case when three orthogonal channels with an 11- Mbps data rate are available

Multichannel Medium Access Control (MAC) protocols for IoT can potentially improve network performance. Therefore, a considerable number of such protocols have been proposed in the last decade, ranging from slotted synchronous to contention-based asynchronous multichannel protocols. In this paper two of the most representative multichannel MAC layer protocols are compared: Time-Slotted Channel Hopping (TSCH) using the Orchestra scheduling algorithm, and Energy-Efficient Multichannel MAC (EM-MAC). The performance of these protocols is assessed under different traffic loads and node densities using the standard IPv6 Routing Protocol for Low-Power and Lossy Networks (LLNs), i.e. RPL. The results show the cross-layer interaction between the RPL protocol and the multichannel MAC schemes under study. Moreover, it can be generally appreciated that TSCH/Orchestra performs better in terms of Packet Delivery Ratio (PDR) whereas EM-MAC exhibits lower power consumption. These characteristics reveal the suitability of these protocols for different IoT applications.

Directional antennas in Ad hoc networks offer more benefits than the traditional antennas with omni-directional mode. With directional antennas, it can increase the spatial reuse of the wireless channel. A higher gain of directional antennas makes terminals a further transmission range and fewer hops to the destination. This paper presents the design, implementation and simulation results of a multi-channel Medium Access Control (MAC) protocols for dense Vehicular Ad hoc Networks using directional antennas with local beam tables. Numeric results show that our protocol performs better than the existing multichannel protocols in vehicular environment.

In recent years, multi-channel MACs have attracted considerable attention in wireless networking research. Motivation for research into multi-channel MACs is their potential to increase the capacity of wireless ad hoc networks by exploiting multiple orthogonal frequency bands. This potential has been confirmed by several simulation studies that reported promising results for multi-channel MACs. However, the analytical performance of these protocols is not well understood. In this work, we present an analytical framework for modeling the performance multi-channel MACs in multi-hop networks. We employ our framework to investigate the performance of three representative multi channel MACs: Asynchronous Multichannel Coordination Protocol (AMCP), Multi-Channel MAC (MMAC), and Slotted Seeded Channel Hopping (SSCH). The important findings of our analysis are: (1) SSCH outperforms AMCP and MMAC in both 802.11b and 802.11a scenario, (2) AMCP performs worse than MMAC in 802.11b because the overhead of AMCP's control channel is higher than that of MMAC's control interval, and (3) the overhead of AMCP's control channel becomes negligible in an 802.11a scenario and is outweighed by that of MMAC's control interval. For this reason, AMCP delivers better performance than MMAC in 802.11a scenario.

Designing QoS-aware medium access control (MAC) scheme is a challenging issue in vehicular ad hoc networks. Proportional fairness and bandwidth utilization are among the significant requirements that should be taken into account by a MAC scheme. In this paper, a bandwidth-efficient and fair multichannel MAC protocol is proposed to address these two requirements, specifically in vehicle-to-vehicle communications. The proposed scheme is based on clustering of vehicles and exploits time division multiple access (TDMA) method alongside the carrier sense multiple access with collision avoidance mechanism to allocate DSRC-based resources in a different manner from IEEE 802.11p/IEEE 1609.4 protocols. It divides each channel into aligned dynamic-sized time frames. In each time frame, in a fully TDMA-based period, transmission opportunities are assigned to vehicles letting them have dedicated transmissions on the service and control channels. The maximum number of transmission opportunities per each frame is determined by the cluster head (CH) based on a defined optimization problem which aims at maximizing both proportional fairness and bandwidth utilization. Furthermore, the bandwidth utilization is assumed to be enhanced more through reallocation of unused transmission opportunities in each time frame, using a proposed reallocation algorithm. The proposed MAC protocol is treated as a lightweight scheme such that various types of unicast, multicast and broadcast communications are possible within the cluster without involving the CH. Evaluation results show that the proposed scheme has more than 90 % achievement in terms of proportional fairness and bandwidth utilization simultaneously, and in this case, has a considerable superiority over TC-MAC. In addition, using the proposed scheme, the satisfaction level of vehicles is preserved appropriately.

In this paper, we propose and investigate an efficient multichannel Medium Access Control (MAC) protocol for Cognitive Radio Ad Hoc Networks (CRAHNs). The proposed protocol supports Secondary Users' (SUs) dynamic utilization of the licensed channel of Primary Users (PUs) to enable the SUs' performance of a multichannel data transmission simultaneously and without interfering with each other. The proposed protocol can be cooperative or non-cooperative. The cooperative protocol scheme enables a SU to sense PU's presence independently in a multichannel architecture and then broadcasts the report to its neighbors in a proactive fashion. The performance of the cooperative and non-cooperative protocol schemes is simulated and compared. The performance demonstration focuses not only on the SU performance but also on the PU's performance with an Ad hoc On-demand Distance Vector (AODV) routing protocol. The simulation results show that the proposed protocol enhances the network utilizations in general and that the cooperative scheme significantly enhances the Packet Delivery Ratio (PDR) and decreases the end-to-end delay of SUs with high traffic PU connections.

Recent development has a tremendous growth in the ad-hoc wireless networks. Ad-hoc wireless networks are dynamic topology networks organized by a collection of mobile nodes that utilize multi-hop radio relaying and are capable of operating without the support of any fixed infrastructure. Ad-hoc wireless networks are very useful in emergency operations, collaborative and distributed computing and military applications. Multicasting plays an important role in the ad-hoc wireless networks, where nodes form groups to carry out certain tasks that require point-to-multipoint and multipoint-to-multipoint voice and data communication. The biggest challenge in the ad-hoc wireless networks is to find an optimized path between the two nodes. In this paper, we present an ant colony based metaheuristic multicast routing protocol for ad-hoc wireless networks, in that we analyzed the performance of dynamic core based multicast routing protocol (DCMP). This approach maps the solution capability of swarm intelligence to mathematical and engineering problems. The DCMP is highly adaptive, efficient and scalable. The performance of these protocols has been examined under realistic scenarios using NS 2, the network simulator tool. Performance has been analyzed for the metrics packet delivery ratio and control overheads with the multicast routing protocol. The proposed ant colony based routing protocol reduce the overheads in routing.

Cognitive Radio (CR) exploits underutilized licensed spectrums to improve its bandwidth availability. Using CR technology, a node is able to adapt its transmission and reception radio parameters including channel frequency dynamically according to local spectrum availability. For channel access between wireless nodes, a cognitive Medium Access Control (MAC) protocol is necessary to coordinate the CRs. Multi-channel MAC protocol extensions have been proposed in IEEE802.11 to enable a node to operate in multiple channels in order to improve network-wide throughput. These multi-channel MAC protocols have several functions that can be leveraged by cognitive MAC protocols due to their similarities in certain aspects, though the CR has an additional requirement to cope with the existence of licensed users that have higher authority over the channels. Current research in cognitive MAC protocols assumes the availability of a common control channel at all times, which is an approach in the multi-channel MAC protocols. This approach has certain hardware requirements that may not be readily available at CR nodes. Hence, other approached may be necessary. In this paper, various types of multi-channel MAC protocols are reviewed, followed by discussion of their merits and demerits in multi-channel environments. The purpose is to show the additional functionalities and challenges that each multi-channel MAC protocol has to offer and address in order to operate in multihop CR networks. By providing discussion on possible technology leverage from multi-channel to cognitive MAC protocols, we aim to establish a foundation for further research and discussion.

IEEE 802.11p is a communication protocol which is extended by IEEE 802.11 standard, mainly used in Vehicular Ad-Hoc Networks (VANETs). VANETs generally include the Service Channel (SCH) and Control Channel (CCH). In the traditional 802.11p protocol, the length ratio between CCH and SCHs is fixed. This paper presents a variable SCH interval(VSI) multichannel medium access control (MAC) scheme under the non-saturated channel. Under this scheme, we can control the length of CCH interval and SCH interval. This paper uses three-dimensional Markov chain model to calculate the delay of WAVE service announcement (WSA) frame. We propose a VSI MAC calculation model under unsaturated condition to achieve the maximum throughput. The simulation results indicate that the proposed scheme can help VANETs increase the unsaturated throughput of SCHs and lower the transmission delay of data frames obviously.

In mobile ad-hoc network, some multi-channel MAC protocols utilize multiple channels to reduce the collision of wireless transmission and thus get high throughput. These multi-channel MAC protocols aim at improving the performance of unicast communication, and multicast data are generally transmitted as broadcast. So multicast cannot benefit from the multi-channel technique. This paper proposes a multi-channel media access control protocol for multicast (MCMAC) which uses multi-channel techniques to improve multicast performance. To improve the reliability of MAC layer, we extended a reliable multi-channel MAC protocol for multicast (RMCMAC) based on MCMAC. Taking ODMRP [S.-J. Lee et al., 2000] as an example of multicast routing protocols, we evaluate the multicast performance of MCMAC and RMCMAC for ad hoc networks via detailed simulation.